1. Field of the Invention
The present invention relates to a fuel supply system for feeding under pressure a fuel within a fuel tank into an injector for an internal combustion engine for vehicle, and more particularly to a fuel supply system that is operated by a driving force of a DC motor.
2. Description of the Related Art
The conventional fuel supply system comprises a fuel pump portion for sucking and discharging fuel within the fuel tank, a motor portion for driving the fuel pump portion, and a barrel-like fuel filter for accommodating a filter medium filtering the fuel containing an abrasion powder produced when the motor portion is driven in the fuel.
In the above fuel supply system, when a power source is turned on, a rotor of the motor portion is rotated, and a pump mechanism is activated to suck a fuel within the fuel tank into the fuel pump portion, the sucked fuel entering a casing for the fuel filter. Within the casing, the fuel is passed through the filter medium to remove the dirt containing abrasion powder produced by the brush or commutator in the motor portion.
Thereafter, the fuel is passed through the fuel filter, and then fed under pressure through a discharge opening via a pipeline into the injector for the internal combustion engine for vehicle (e.g., refer to JP-A-8-284769).
The conventional fuel supply system as constituted above had a drawback that because it has a structure in which the fuel discharged from the fuel pump portion is passed through the motor portion to the fuel filter portion, the debris contained in the fuel, for example, abrasion powder from the brush or commutator forming the motor portion is once expelled from the motor portion, and then flowed back to the motor portion to deposit on or stick to a driving portion of the motor portion, thereby degrading the function of the fuel supply system.